1. Field of the Invention
The present invention relates to a linear motor system, a movable body system, and an electrical angle estimating method.
2. Description of Related Art
A linear motor system has been used for a movable body system such as a transport vehicle system. A movable body system including a movable body (a transport vehicle) and a movement route (track) for the transport vehicle is known. The track includes magnets which are arrayed such that polarities, south and north poles, are alternately different. The transport vehicle includes armatures (a first motor and a second motor). The above magnets and armatures constitute a linear motor. The transport vehicle is provided with magnetic detection parts that detect a magnetic field generated by the magnets. The linear motor is driven and controlled by using an electrical angle calculated from outputs of the magnetic detection parts.
The magnetic detection parts are provided on front and rear sides of the transport vehicle in a movement direction with respect to the armatures. However, the magnetic detection parts as thus disposed are distant from the armatures and thus disadvantageous in highly accurate drive control. For example, at the time of the transport vehicle taking a curve, in the positional relation between the magnets and the magnetic detection parts, positional displacement between the magnets and the armatures increases, resulting in a large error included in an electrical angle calculated from detection results of the magnetic detection parts. In order to cope with this problem, there has been proposed a linear motor in which each of magnetic detection parts is disposed on an armature.
When each of the magnetic detection part is disposed on the armature as described above, the magnetic detection parts are influenced by excitation of the armatures, leading to a large error included in an electrical angle calculated from detection results of the magnetic detection parts. The present invention has been made in view of the circumstances described above, and it is an object of the present invention to provide a linear motor system, a movable body system, and an electrical angle estimating method, which are capable of estimating an electrical angle with high accuracy.